The present invention relates to polymeric supports suitable for use in association with catalysts, preferably single site type catalysts, activated with aluminoxane. Particularly the supports contain functional groups.
There are a number of patents that disclose the use of polymeric supports of olefin polymerization catalysts. Generally the supports are polyolefins as illustrated for example by Atlantic Richfield""s U.S. Pat. No. 4,407,727; Quantum""s WO 96/35726; and the abstract of Mitsubishi""s JP 67407. Polyethylene and polypropylene are not polymers prepared from C4-12 vinyl monomers and thus the references do not teach or disclose the subject matter of the present patent application.
There are a fairly large number of patents which teach using polymeric supports comprising styrene optionally a cross-linking agent such as divinyl benzene and/or polymeric supports such as poly(methyl methacrylate). These patents are illustrated by U.S. Pat. Nos. 4,623,707; 4,623,912; 5,139,985; 4,900,706; 5,463,000; 5,118,648; 5,498,582; and EP 344 755.
The closest art Applicants are aware relevant to the subject matter of the present patent application are U.S. Pat. No. 5,362,824 issued Nov. 8, 1994 and U.S. Pat. No. 5,461,017 issued Oct. 24, 1995 both to Furtek et al., assigned to Mobil. The patent teaches a polymeric support comprising about 30% of divinyl benzene, about 55% of styrene and about 15% of acetoxy or hydroxy styrene. The support may be used in association with a metallocene catalyst and aluminoxane as an activator. The reference does not suggest functional monomers selected from the group consisting of C1-8 hydroxy esters of C3-6 ethylenically unsaturated carboxylic acids, chloride derivatives thereof, chlorostyrene and C1-8 straight chain, branched or cyclic amines which are unsubstituted or substituted by up to two C1-4 alkyl radicals at the nitrogen atom.
The present invention provides a functionalized polymeric support for use in association with a catalyst system comprising a co-catalyst of the formula R12AlO(R1AlO)mAlR12 wherein each R1 is independently selected from the group consisting of C1-20 hydrocarbyl radicals and m is from 3 to 50, said support comprising the suspension or emulsion polymerization product of a feedstock comprising:
(i) from 0 to 95 weight % of one or more C4-12 vinyl monomers;
(ii) from 50 to 2 weight % of a crosslinking agent; and
(iii) from 70 to 3 weight % of a functionalized monomer
containing a reactive functional group selected from the group consisting of C1-8 hydroxy esters of C3-6 ethylenically unsaturated carboxylic acids, chloride derivatives thereof, chlorostyrene and C1-8 straight chain, branched or cyclic amines which are unsubstituted or substituted by up to two C1-4 alkyl radicals at the nitrogen atom; the sum of the weight % of said monomers being 100 weight %, and having a particle size from 0.1 to 1000 microns, surface area of greater than 10 m2/g and a pore volume of at least 0.2 cc/g of support.
A further aspect of the present invention provides a supported co-catalyst of the formula R12AlO(R1AlO)mAlR12 wherein each R1 is independently selected from the group consisting of C1-20 hydrocarbyl radicals and m is from 3 to 50 on the above functional support, wherein the co-catalyst is present on the support in an amount from 0.01 to 0.8 g per g of support.
A further aspect of the present invention provides a catalyst system comprising the above supported co-catalyst, together with a catalyst of the formula:
(L)nxe2x80x94Mxe2x80x94(X)p
wherein M is a transition metal; L is a monoanionic ligand independently selected from the group consisting of a cyclopentadienyl-type ligand, a bulky heteroatom ligand and a phosphinimine ligand; X is an activatable ligand; n may be from 1 to 3; and p may be from 1 to 3, provided that the sum of n+p equals the valence state of M, and further provided that two L ligands may be bridged by a silyl radical or a C1-4 alkyl radical to provide a molar ratio of aluminum to transition metal from 5:1 to 1000:1.
A further aspect of the present invention provides a supported catalyst comprising the above noted support, and a catalyst of the formula:
(L)nxe2x80x94Mxe2x80x94(X)p
wherein M is a transition metal; L is a monoanionic ligand selected independently from the group consisting of a cyclopentadienyl-type ligand, a bulky heteroatom ligand and a phosphinimine ligand; X is an activatable ligand; n may be from 1 to 3; and p may be from 1 to 3, provided that the sum of n+p equals the valence state of M, and further provided that two L ligands may be bridged by a silyl radical or a C1-4 alkyl radical.
A further aspect of the present invention provides the above noted catalyst system together with a co-catalyst of the formula R12AlO(R1AlO)mAlR12 wherein each R1 is independently selected from the group consisting of C1-20 hydrocarbyl radicals and m is from 3 to 50.
A further aspect of the present invention provides a catalyst system comprising a mixture of a catalyst of the formula:
(L)nxe2x80x94Mxe2x80x94(X)p
wherein M is a transition metal; L is a monoanionic ligand selected from the group consisting of a cyclopentadienyl-type ligand, a bulky heteroatom ligand and a phosphinimine ligand; X is an activatable ligand; n may be from 1 to 3; and p may be from 1 to 3, provided that the sum of n+p equals the valence state of M, and further provided that two L ligands may be bridged by a silyl radical or a C1-4 alkyl radical and a co-catalyst of the formula R12AlO(R1AlO)mAlR12 wherein each R1 is independently selected from the group consisting of C1-20 hydrocarbyl radicals and m is from 3 to 50 to provide a molar ratio of aluminum to transition metal from from 5:1 to 1000:1 on the above noted support.
A further aspect of the present invention provides the above noted catalyst systems in a gas phase or slurry polymerization, preferably for olefins.
The feedstock for the polymeric supports of the present invention comprises:
(i) from 0 to 95, preferably from 60 to 80, weight % of one or more C4-12 vinyl monomers;
(ii) from 50 to 2, preferably from 25 to 10, weight % of a crosslinking agent; and
(iii) from 70 to 3, preferably from 65 to 15, most preferably from 60 to 15, desirably from 50 to 15 weight % of a functionalized monomer containing reactive functional group selected from the group consisting of C1-8 hydroxy esters of C3-6 ethylenically unsaturated carboxylic acids, chloride derivatives thereof, chlorostyrene and C1-8 straight chain, branched or cyclic amines which are unsubstituted or substituted by up to two C1-4 alkyl radicals at the nitrogen atom; the sum of the weight % of said monomers being 100 weight %.
Some vinyl monomers include styrene, alpha-methyl styrene, para-methyl styrene and C1-4 alkyl esters of C3-6 unsaturated carboxylic acids. The styrenic monomers such as styrene, alpha-methyl styrene, para-methyl styrene may also be referred to as vinyl aromatic monomers. Some C1-4 alkyl esters of C3-6 unsaturated carboxylic acids include methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate and butyl acrylate.
Some crosslinking agents include divinyl benzene, divinyl toluene, di- and tri-acrylates and di- and tri-methacrylates such as pentaerythritol trimethacrylate.
Some functionalized monomers include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and pyridine.
The functionalized polymeric supports may be prepared by conventional suspension polymerization techniques. These are well known to those skilled in the art. Generally the monomers are dispersed in water as continuous phase using one or more surfactant or suspending agents which may be ionic such as long chain (e.g. C12-18) fatty acids or derivatives thereof (e.g. sulfonates) and salts thereof such as for example, dodecyl benzene sulfonate, or a non ionic surfactant such as polyoxyethylene sorbitan fatty acid esters (such as those sold under the trademark TWEEN). Typically the emulsion also contains a free radical initiator (such as persulfates (optionally in the presence of a reducing agent) or peroxides). The emulsion is heated to begin polymerization and the polymerization may be completed in a batch process.
The selection of the surfactants to some extent controls the particle size of the final particles in the emulsion polymerization.
Generally the polymeric particles will have a particle size from 0.1 to 1000, preferably from 10 to 300 microns, surface area of greater than 10, preferably from 100 to 1500 m2/g and a pore volume of at least 0.2, preferably at least 0.6 cc/g of support.
There are several methods which may be used to increase the pore size/volume in the polymeric particles. For example silica may be incorporated into the polymer then dissolved out using a strong base. Silica impregnated with a blowing agent may be incorporated into the polymeric particles and then the blowing agent may be activated. The residual silica may again be dissolved from the polymer particles. This technique is disclosed in U.S. Pat. No. 5,168,104 issued Dec. 1, 1992 to Li et al.
The co-catalysts useful in the present invention are aluminoxanes also sometimes called alumoxanes. The aluminoxane compounds of the present invention have the formula I: R12AlO(R1AlO)mAlR12 wherein each R1 is independently selected from the group consisting of C1-20 hydrocarbyl radicals and m is from 3 to 50, preferably from 3 to 30, most preferably from 5 to 30. Most preferably R1 is selected from the group consisting of C1-6, most preferably C1-4 straight chained or branched alkyl radicals. Suitable alkyl radicals include a methyl radical, an ethyl radical, an isopropyl radical and an isobutyl radical. In some commercially available aluminoxanes R1 is a methyl radical.
In one aspect of the present invention the co-catalyst may be supported on the support in an amount from 0.01 to 0.8, preferably from 0.01 to 0.4, most preferably from 0.02 to 0.3 g per g of support (e.g. 1 to 80, preferably 1 to 40, most preferably 2 to 30 weight %).
In a further aspect the present invention the supported co-catalyst may be used in conjunction with a single site catalyst.
Typically the catalysts used with the aluminoxane, prepared in accordance with the present invention, comprise a transition metal complex of at least one C5-13 ligand containing a 5-membered carbon ring having delocalized bonding within the ring and bound to the metal atom through covalent xcex75 bonds; and said ligand being unsubstituted or up to fully substituted with one or more substituents as described below.
Generally the catalyst may be a single site type catalyst typically comprising a transition metal, preferably an early transition metal (e.g. Ti, V, Zr and Hf) and generally having two bulky ligands. In many of the well known single site catalysts typically one of the bulky ligands is a cyclopentadienyl-type ligand. These cyclopentadienyl-type ligands comprise a C5-13 ligand containing a 5-membered carbon ring having delocalized bonding within the ring and bound to the metal atom through covalent xcex75 bonds which are unsubstituted or may be further substituted (sometimes referred to in a short form as Cp ligands). Cyclopentadienyl-type ligands include unsubstituted cyclopentadienyl, substituted cyclopentadienyl, unsubstituted indenyl, substituted indenyl, unsubstituted fluorenyl and substituted fluorenyl. An exemplary list of substituents for a cyclopentadienyl-type ligand includes the group consisting of C1-10 hydrocarbyl radicals (including phenyl and benzyl radicals), which hydrocarbyl substituents are unsubstituted or further substituted by one or more substituents selected from the group consisting of a halogen atom, preferably a chlorine or fluorine atom and a C1-4 alkyl radical; a C1-8 alkoxy radical; a C6-10 aryl or aryloxy radical; an amido radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals; a phosphido radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals; silyl radicals of the formula xe2x80x94Sixe2x80x94(R)3 wherein each R is independently selected from the group consisting of hydrogen, a C1-8 alkyl or alkoxy radical, and C6-10 aryl or aryloxy radicals; and germanyl radicals of the formula xe2x80x94Gexe2x80x94(R)3 wherein R is as defined directly above.
If there are two such bulky ligands (i.e. bis-Cp) the catalysts are metallocene-type catalysts. The Cp ligand may be bridged to another Cp ligand by a silyl bridge or a short chain (C1-4) alkyl radical. The Cp-type ligand may be bridged to an amido radical which may be further substituted by up to two additional substituents. Such bridged complexes are sometimes referred to as constrained geometry catalysts.
Broadly, the transition metal complex (or catalyst) suitable for use in the present invention has the formula:
(L)nxe2x80x94Mxe2x80x94(X)p
wherein M is a transition metal preferably selected from the group consisting of Ti, V, Zr, Hf, Cr, Fe, Co, Ni and Pd, most preferably selected from the group consisting of Ti, Hf and Zr (as described below); L is a monoanionic ligand independently selected from the group consisting of a cyclopentadienyl-type ligand, a bulky heteroatom ligand (as described below) and a phosphinimine ligand (as described below); X is an activatable ligand which is most preferably a simple monoanionic ligand such as alkyl or a halide (as described below); n may be from 1 to 3, preferably 2 or 3; and p may be from 1 to 3, preferably 1 or 2, provided that the sum of n+p equals the valence state of M, and further provided that two L ligands may be bridged by a silyl radical or a C1-4 alkyl radical.
If one or more of the L ligands is a phosphinimine ligand the transition metal complex may be of the formula: 
wherein M is a transition metal preferably selected from Ti, Hf and Zr (as described below); Pl is a phosphinimine ligand (as described below); L is a monoanionic ligand selected from the group consisting of a cyclopentadienyl-type ligand or a bulky heteroatom ligand (as described below); X is an activatable ligand which is most preferably a simple monoanionic ligand such as an alkyl or a halide (as described below); m is 1 or 2; n is 0 or 1; and p is an integer fixed by the valence of the metal M (i.e. the sum of m+n+p equals the valence state of M).
In one embodiment the catalysts are group 4 metal complexes in the highest oxidation state. For example, the catalyst may be a bis (phosphinimine) dichloride complex of titanium, zirconium or hafnium. Alternately, the catalyst contains one phosphinimine ligand, one xe2x80x9cLxe2x80x9d ligand (which is most preferably a cyclopentadienyl-type ligand) and two xe2x80x9cXxe2x80x9d ligands (which are preferably both chloride).
The preferred metals (M) are from Group 4 (especially titanium, hafnium or zirconium) with titanium being most preferred.
The catalyst may contain one or two phosphinimine ligands which are covalently bonded to the metal. The phosphinimine ligand is defined by the formula: 
wherein each R3 is independently selected from the group consisting of a hydrogen atom; a halogen atom; C1-20, preferably C1-10 hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom; a C1-8 alkoxy radical; a C6-10 aryl or aryloxy radical; an amido radical; a silyl radical of the formula:
xe2x80x94Sixe2x80x94(R2)3
wherein each R2 is independently selected from the group consisting of hydrogen, a C1-8 alkyl or alkoxy radical, and C6-10 aryl or aryloxy radicals; and a germanyl radical of the formula:
xe2x80x94Gexe2x80x94(R2)3
wherein R2 is as defined above.
The preferred phosphinimines are those in which each R3 is a hydrocarbyl radical, preferably a C1-6 hydrocarbyl radical. A particularly preferred phosphinimine is tri-(tertiary butyl) phosphinimine (i.e. wherein each R3 is a tertiary butyl group).
Preferred phosphinimine catalysts are Group 4 organometallic complexes which contain one phosphinimine ligand (as described above) and one ligand L which is either a cyclopentadienyl-type ligand or a heteroligand.
As used herein, the term xe2x80x9cheteroligandxe2x80x9d refers to a ligand which contains at least one heteroatom selected from the group consisting of boron, nitrogen, oxygen, phosphorus or sulfur. The heteroligand may be sigma or pi-bonded to the metal. Exemplary heteroligands include ketimide ligands, silicone-containing heteroligands, amido ligands, alkoxy ligands, boron heterocyclic ligands and phosphole ligands, as all described below.
As used herein, the term xe2x80x9cketimide ligandxe2x80x9d refers to a ligand which:
(a) is bonded to the transition metal via a metal-nitrogen atom bond;
(b) has a single substituent on the nitrogen atom (where this single substituent is a carbon atom which is doubly bonded to the N atom); and
(c) has two substituents Sub 1 and Sub 2 (described below) which are bonded to the carbon atom.
Conditions a, b and c are illustrated below: 
The substituents xe2x80x9cSub 1xe2x80x9d and xe2x80x9cSub 2xe2x80x9d may be the same or different. Exemplary substituents include hydrocarbyls having from 1 to 20 carbon atoms, silyl groups, amido groups and phosphido groups. For reasons of cost and convenience it is preferred that these substituents both be hydrocarbyls, especially simple alkyls and most preferably tertiary butyl.
Silicon containing heteroligands are defined by the formula:
xe2x80x94(xcexc)SiRxRyRz
wherein the xe2x80x94 denotes a bond to the transition metal and xcexc is sulfur or oxygen.
The substituents on the Si atom, namely Rx, Ry and Rz are required in order to satisfy the bonding orbital of the Si atom. The use of any particular substituent Rx, Ry or Rz is not especially important to the success of this invention. It is preferred that each of Rx, Ry and Rz is a C1-2 hydrocarbyl group (i.e. methyl or ethyl) simply because such materials are readily synthesized from commercially available materials.
The term xe2x80x9camidoxe2x80x9d is meant to convey its broad, conventional meaning. Thus, these ligands are characterized by (a) a metal-nitrogen bond and (b) the presence of two substituents (which are typically simple alkyl or silyl groups) on the nitrogen atom.
The terms xe2x80x9calkoxyxe2x80x9d and xe2x80x9caryloxyxe2x80x9d is also intended to convey its conventional meaning. Thus, these ligands are characterized by (a) a metal oxygen bond and (b) the presence of a hydrocarbyl group bonded to the oxygen atom. The hydrocarbyl group may be a C1-10 straight chained, branched or cyclic alkyl radical or a C6-13 aromatic radical which radicals are unsubstituted or further substituted by one or more C1-4 alkyl radicals (e.g. 2,6 di-tertiary butyl phenoxy).
Boron heterocyclic ligands are characterized by the presence of a boron atom in a closed ring ligand. This definition includes heterocyclic ligands which also contain a nitrogen atom in the ring. These ligands are well known to those skilled in the art of olefin polymerization and are fully described in the literature (see, for example, U.S. Pat. Nos. 5,637,659; 5,554,775; and the references cited therein).
The term xe2x80x9cphospholexe2x80x9d is also meant to convey its conventional meaning. xe2x80x9cPhospholesxe2x80x9d are cyclic dienyl structures having four carbon atoms and one phosphorus atom in the closed ring. The simplest phosphole is C4PH4 (which is analogous to cyclopentadiene with one carbon in the ring being replaced by phosphorus). The phosphole ligands may be substituted with, for example, C1-20 hydrocarbyl radicals (which may, optionally, contain halogen substituents); phosphido radicals; amido radicals; or silyl or alkoxy radicals. Phosphole ligands are also well known to those skilled in the art of olefin polymerization and are described as such in U.S. Pat. No. 5,434,116 (Sone, to Tosoh).
The term xe2x80x9cactivatable ligandxe2x80x9d or xe2x80x9cleaving ligandxe2x80x9d refers to a ligand which may be activated by the aluminoxane (also referred to as an xe2x80x9cactivatorxe2x80x9d) to facilitate olefin polymerization. Exemplary activatable ligands are independently selected from the group consisting of a hydrogen atom; a halogen atom, preferably a chlorine or fluorine atom; a C1-10 hydrocarbyl radical, preferably a C1-4 alkyl radical; a C1-10 alkoxy radical, preferably a C1-4 alkoxy radical; and a C5-10 aryl oxide radical; each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may be unsubstituted by or further substituted by one or more substituents selected from the group consisting of a halogen atom, preferably a chlorine or fluorine atom; a C1-8 alkyl radical, preferably a C1-4 alkyl radical; a C1-8 alkoxy radical, preferably a C1-4 alkoxy radical; a C6-10 aryl or aryloxy radical; an amido radical which is unsubstituted or substituted by up to two C1-8, preferably C1-4 alkyl radicals; and a phosphido radical which is unsubstituted or substituted by up to two C1-8, preferably C1-4 alkyl radicals.
The number of activatable ligands depends upon the valency of the metal and the valency of the activatable ligand. The preferred catalyst metals are Group 4 metals in their highest oxidation state (i.e. 4+) and the preferred activatable ligands are monoanionic (such as a halidexe2x80x94especially chloride or C1-4 alkylxe2x80x94especially methyl). One useful group of catalysts contain a phosphinimine ligand, a cyclopentadienyl ligand and two chloride (or methyl) ligands bonded to the Group 4 metal. In some instances, the metal of the catalyst component may not be in the highest oxidation state. For example, a titanium (III) component would contain only one activatable ligand.
As noted above, one group of catalysts is a Group 4 organometallic complex in its highest oxidation state having a phosphinimine ligand, a cyclopentadienyl-type ligand and two activatable ligands. These requirements may be concisely described using the following formula for the preferred catalyst: 
wherein: M is a metal selected from Ti, Hf and Zr; Pl is as defined above, but preferably a phosphinimine wherein R3 is a C1-6 alkyl radical, most preferably a t-butyl radical; L is a ligand selected from the group consisting of cyclopentadienyl, indenyl and fluorenyl ligands which are unsubstituted or substituted by one or more substituents selected from the group consisting of a halogen atom, preferably chlorine or fluorine; C1-4 alkyl radicals; and benzyl and phenyl radicals which are unsubstituted or substituted by one or more halogen atoms, preferably fluorine; X is selected from the group consisting of a chlorine atom and C1-4 alkyl radicals; m is 1; n is 1; and p is 2.
In one embodiment of the present invention the transition metal complex may have the formula: [(CP)qM[Nxe2x95x90P(R3)]bXc wherein M is the transition metal; Cp is a C5-13 ligand containing a 5-membered carbon ring having delocalized bonding within the ring and bound to the metal atom through covalent xcex75 bonds and said ligand being unsubstituted or up to fully substituted with one or more substituents selected from the group consisting of a halogen atom, preferably chlorine or fluorine; C1-4 alkyl radicals; and benzyl and phenyl radicals which are unsubstituted or substituted by one or more halogen atoms, preferably fluorine; R3 is a substituent selected from the group consisting of C1-10 straight chained or branched alkyl radicals, C6-10 aryl and aryloxy radicals which are unsubstituted or may be substituted by up to three C1-4 alkyl radicals, and silyl radicals of the formula xe2x80x94Sixe2x80x94(R)3 wherein R is C1-4 alkyl radical or a phenyl radical; L is selected from the group consisting of a leaving ligand; q is 1 or 2; b is 1 or 2; and the valence of the transition metalxe2x80x94(q+b)=c.
The catalysts systems in accordance with the present invention may have a molar ratio of aluminum from the aluminoxane to transition metal from 5:1 to 1000:1, preferably from 5:1 to 300:1, most preferably from 30:1 to 300:1, most desirably from 50:1 to 120:1.
In a further embodiment of the present invention the above noted catalyst may be supported on the above noted polymeric support. The catalyst may be loaded on the support to provide from 0.01 to 5, preferably from 0.05 to 2, most preferably from 0.1 to 1 weight % of transition metal per g of support.
In a further embodiment of the present invention the aluminoxane and the above noted catalyst may be premixed in the ratios specified above (e.g. from 5:1 to 1000:1, preferably from 5:1 to 300:1, most preferably from 30:1 to 300:1, most desirably from 50:1 to 120:1) and the resulting mixture may be supported on the functionalized polymeric catalyst support. These ratios may be broadly used with the catalyst and activator regardless of the sequence of deposition on the support.
In supporting the aluminoxane, catalyst or mixture on the polymeric support conventional techniques may be used. The support in a hydrocarbyl diluent may be contacted with the aluminoxane or the catalyst or a mixture thereof in the same or a compatible hydrocarbyl solvent or diluent. The resulting treated polymeric support may be separated from the bulk of the solvent or diluent by decanting or by drying typically from room temperature (20xc2x0 C.) to about 60xc2x0 C., preferably under vacuum (of less than about 10 torr) optionally while passing an inert gas such as nitrogen through the separated support and diluent/solvent. It should be noted the polymeric support may swell in the solvent or diluent but should not readily dissolve because it is crosslinked. It may be possible to spray dry the polymeric support together with the aluminoxane and or catalyst.
Inert hydrocarbon solvents typically comprise a C4-12 hydrocarbon which may be unsubstituted or substituted by a C1-4 alkyl group, such as butane, pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane or hydrogenated naphtha. An additional solvent is Isopar E (C8-12 aliphatic solvent, Exxon Chemical Co.).
The polymerization in accordance with the present invention may be conducted in a liquid phase as either a slurry or solution polymerization conducted in an inert diluent or solvent, or gas phase polymerization. The difference between slurry and solution polymerization being whether the resulting polymer is soluble in the liquid phase.
Solution and slurry polymerization processes are fairly well known in the art. These processes are conducted in the presence of an inert hydrocarbon solvent typically a C4-12 hydrocarbon which may be unsubstituted or substituted by a C1-4 alkyl group such as butane, pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane or hydrogenated naphtha. An additional solvent is Isopar E (C8-12 aliphatic solvent, Exxon Chemical Co.).
The polymerization may be conducted at temperatures from about 20xc2x0 C. to about 250xc2x0 C. Depending on the product being made, this temperature may be relatively low such as from 20xc2x0 C. to about 180xc2x0 C., typically from about 80xc2x0 C. to 150xc2x0 C. and the polymer is insoluble in the liquid hydrocarbon phase (diluent) (e.g. a slurry polymerization). The reaction temperature may be relatively higher from about 180xc2x0 C. to 250xc2x0 C., preferably from about 180xc2x0 C. to 230xc2x0 C. and the polymer is soluble in the liquid hydrocarbon phase (solvent). The pressure of the reaction may be as high as about 15,000 psig for the older high pressure processes or may range from about 15 to 4,500 psig.
In the gas phase polymerization of a gaseous mixture comprising from 0 to 15 mole % of hydrogen, from 0 to 30 mole % of one or more C3-8 alpha olefins, from 15 to 100 mole % of ethylene, and from 0 to 75 mole % of an inert gas at a temperature from 50xc2x0 C. to 120xc2x0 C., preferably from 75xc2x0 C. to about 110xc2x0 C., and at pressures typically not exceeding 3447 kPa (about 500 psi), preferably not greater than 2414 kPa (about 350 psi).
Suitable olefin monomers may be ethylene and C3-20 mono- and diolefins. Preferred monomers include ethylene and C3-12 alpha olefins which are unsubstituted or substituted by up to two C1-6 alkyl radicals. Illustrative non-limiting examples of such alpha olefins are one or more of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene. The polymers prepared in accordance with the present invention have a good molecular weight. That is, weight average molecular weight (Mw) will preferably be greater than about 30,000 ranging up to 107, preferably 105 to 107. Hydrogen may be used in the polymerization to control the molecular weight of the polymer.
The polyethylene polymers which may be prepared in accordance with the present invention typically comprise not less than 60, preferably not less than 70, most preferably not less than 80 weight % of ethylene and the balance of one or more C4-10 alpha olefins, preferably selected from the group consisting of 1-butene, 1-hexene and 1-octene.
The present invention will now be illustrated by the following non-limiting examples. In the examples unless otherwise indicated parts means part by weight (i.e. grams) and percent means weight percent.
The following abbreviations are used in the Examples: